Abstract: Assessing the accuracy of guidance system,especially controlling of missile's attitude and station keeping maneuver and landing point forecasting all rely on the reliable trajectory measurement.The refraction error is main error source among the factors effecting measure data accuracy.Among those different refraction error correction approaches applied currently,one is accurate,but its calculation in real-time is very slow.The other is quicker,but its accuracy is unsatisfied because the simplified model of high precision trajectory is used.The fast two-step method of radio wave refraction correction is proposed in this paper.The simulation demonstrates the method meets the requirement of accuracy and speed in project entirely.